Switching to a larger RAID disk
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I use a PC with two RAID arrays. The operating
system currently has a pair of 1TB SSD using Intel Rapid Storage
Technology software, and until recently (February 2023) a pair
of 2TB drives using the Windows RAID feature. Over the years
hard drives have come and gone and when I removed the pair of
2TB disks I noticed one was a Seagate ST2000DM001 dated "15213"
and the other a Seagate ST2000DM006 Barracuda from 12th April
2017. Clearly the latter is a replacement for a failed drive.
The 1TB drives show up as "Drive C" and,
for some historic reason, the larger are "Drive E".
The smaller drives were getting pretty full and lots of data
needed dumping to the larger pair of backup drives but these
were also getting rather full so I decided to just swap the 2T
pair for a 4T pair. I chose two Seagate Skyhawk Surveillance
ST4000VX013 drives which were relatively cheap and I'll now describe
how I managed the swap. |
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The key point in switching to a drive larger
than 2T is the formatting. 2TB is the maximum size that MBR can
handle so one needs to use the later GPT system. The reason is
quite straightforward and is because MBR can only handle a 32
bit address. Over the decades this type of limitation has also
given rise to the large number of different RAM modules types.
If you attempt to use MBR on a 4TB disk you'll discover half
of the disk will be inaccessible.
Anyway here's the procedure I used. |
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First, with the PC turned off I removed the
pair of 2TB drives and fitted the pair of new 4TB drives. The
PC was turned on and once the Desktop was stable I opened the
"Disk Management" facility. Listed here was one entry
for Drive C (actually an Intel RAID pair) labelled "Disk
0", and two new drives as yet unconfigured. To avoid complications
these drives will be given the same letter as the previous 2TB
pair, which is "E". Selecting the first new drive I
allocated "E" and selected GPT. Quite rapidly the first
drive assumed this letter and selecting the second drive a message
suggesting this become a mirror popped up. Simply agreeing to
this produced the desired result giving me two dynamic 3725.90GB
online drives, both labelled "E". Drive 0 has a blue
stripe indicating a Primary Partition and a brown stripe opposite
Drives 1 and 2 indicating a Mirrored Volume.
All drives were marked "Healthy" so it was
safe to proceed.
Of course new E drive was empty so I needed to now
copy the contents of one of the old 2TB drives to the new 4TB
pair. Turning off the PC I plugged in the newer of the 2TB pair.
As the 2TB RAID pair was perfect it didn't really matter which
2TB drive I used, but if one had been dodgy I would have rejected
it in favour of the other.
As Drive E is used for data backup nothing special
needed to be considered in the copying process. In my case the
2TB drive showed up as Drive D and it was straightforward to
copy blocks of folders from D to E. There were no glitches and
everything copied perfectly.
If you're not sure of data integrity, copy folders
in small groups and if a glitch occurs note the bad folder and
try repeating later with the second old drive.
Copying can take several hours.
When I was writing this I noticed that Disk Management
still had a remnant of the earlier 2T pair. This was a line entry
with an unallocated drive letter so I just selected and deleted
this volume.
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